I used the virtmanager to create a virtual machine. The install medium is the debian netinstaller (Version 10, buster). Installation works without problems. Rebooting fails: no boot device found Starting the recovery mode from the netinstaller image: All resources are available, the chroot instance works fine.
# I used the recovery mode to reinstall grub:
grub-install /dev/sda
update-grub
I expected to see the grub dialog while booting. I found the message "no boot device found"